Append elements with list comprehension

Question

Having a list like this:

['foo','spam','bar']

is it possible, using list comprehension, to obtain this list as result?

['foo','ok.foo', 'spam', 'ok.spam', 'bar', 'ok.bar']

Answer 1

In [67]: alist = ['foo','spam', 'bar']

In [70]: [prefix+elt for elt in alist for prefix in ('','ok.') ]
Out[70]: ['foo', 'ok.foo', 'spam', 'ok.spam', 'bar', 'ok.bar']

Answer 2

With list comprehensions, you're creating new lists, not appending elements to an existing list (which may be relevant on really large datasets)

Why does it have to be a list comprehension anyway? Just because python has them doesn't make it bad coding practice to use a for-loop.